TAMPA, Fla. (AP) — A Secret Service agent left a gun in the bathroom of a plane carrying Republican presidential candidate Mitt Romney.

A reporter discovered the gun while the plane was flying from Florida to Indiana on Wednesday. It was quickly retrieved by a Secret Service agent. The weapon belonged to an agent assigned to Romney's security detail.

In Washington, Secret Service spokesman Edwin Donovan says the agency is aware of the incident and that the matter will be handled internally. He would not discuss who left the gun or how it was misplaced.

The agent involved was not on the afternoon flight to Tampa, Fla., the site of the Republican National Convention. Romney is scheduled to accept the presidential nomination on Thursday.